This invention relates generally to network testing, and in particular to a method of identifying network bridge uplink ports.
Standards for ensuring reliable full-duplex transmission of data from one machine to another include the Transmission Control Protocol (TCP) and Internet Protocol (IP), which were merged into the TCP/IP Internet Protocol Suite, and are referred to today as simply the TCP/IP protocols. The operational hierarchy and structure of networks themselves are based on the Open Systems Interconnection (OSI) seven-layer model, which arose from a reference model created by the International Standards Organization as standard ISO/IEC 7498.
Network test and diagnostic instruments necessarily employ the TCP/IP protocols, and appear at the network portal as just another device on the network. These instruments have displays that provide graphic and text information, including showing the user diagrams of entire configured networks, problems detected, protocol statistics, and devices and networks discovered. The discovery system in a sophisticated network test instrument utilizes the echo request-and-reply feature of the Internet Control Message Protocol (ICMP) to differentiate between hosts, interconnect devices such as switchers and routers, servers, printers and Simple Network Monitoring Protocol (SNMP) devices in gathering information about the network.
Operational boundaries with the OSI seven-layer model are created by repeaters, bridges and switches, and routers. For example, bridges and switches operate within layer 2 based on the OSI seven-layer model, while routers are deployed at the operational boundary between layer 2 and layer 3. That is, routers are used to connect a local network to another network, or to connect multiple networks together. In testing interconnected multiple networks, or even testing large networks that employ multiple bridges and switches to interconnect several devices, it is difficult to identify uplink switch ports where such information is not available in the SNMP database, also known as the SNMP Management Information Base (MIB). An uplink port is a switch or bridge port that is connected to another network interconnect device, such as a bridge or a router, and has a Media Access Control (MAC) address of other switches or bridges beyond the immediate physical layer. Heretofore, the user has had to have knowledge of such uplink ports and manually load the MAC addresses, which are physical addresses, into the MIB. This is a major inconvenience for a technician faced with testing and analyzing a network, and without the needed uplink port information incomplete or incorrect test results follow. Identification of trunk ports is crucial in generating accurate network maps and finding the switch port where a specific device is connected.
It would be desirable to incorporate a feature into a network test instrument that would allow it to identify uplink switch ports where such information is not available in the SNMP MIB.